17 February 2021

Need ID for Grass rats from Ethiopia

Could somebody help me with the identification of these Grass rats (presumably Arvicanthis) from Ethiopia

Picture mid and right were taken in the northwestern highlands, 20 km west of Debre Birham; altitude 2700 m (26.11.2020)

Picture left was taken on the Sanetti plateau in Bale Mountains NP; altitude 4000 m (02.12.2020)

Thank you very much in advance

Michael

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9 Comments

  • 17 February 2021
    Peregrine Rowse

    Michael, I am primarily a birder and no expert but the daytime active grass rats I saw near Debre Birhan were identified by leading bird guides Nigel Redman and Merid Gabremichael as Harrington’s Desmonys (Desmonys harringtoni) known locally as Dega Rat. Dega is the local word for high altitude grassland. You photos appear to be the same sp. that I saw.

    The abundant rodent on the Sanetti Plateau we reckoned to be Blick’s Arvicanthis (Arvicanthis blicki).

    I have photos of both species but can’t work out if it is possible to copy them into a comment reply. If you or anyone else thinks my idenfications are wrong I would love to know!

    • 17 February 2021
      Michael Widmer

      Peregrine, thank you very much for your answer. I agree with Blick’s Grass Rat Arvicanthis blicki for the picture on the left. But I disagree with Desmomys harringtoni for the others. According to the description in the HBW, Desmomys harringtoni occurs in forest habitats and is nocturnal. This does not match with my observation (diurnal activity and open habitat).

  • 17 February 2021
    Terry Goble

    The Grass rat at Sanetti look to be Blick’s Grass Rat .

  • 17 February 2021
    Charles Foley

    Hi Michael, yes I think they are both Arvicanthis. As Peregrine and Terry say, the one from Sanetti is Arvicanthis blicki. The other two are most likely A. abyssinicus, given the black stripe down their back. They look a bit small, but it might just be the camera angle. I’m assuming they were found in high grasslands?

  • 17 February 2021
    Vladimir Dinets

    A. blicki is the only Arvicanthis at Sanetti, and A. abyssynicus is the only one at high elevations in the Simiens. There is supposed to be A. niloticus at lower elevations but not in areas commonly visited by birders and mammalwatchers.

    • 17 February 2021
      Vladimir Dinets

      Oops, sorry, I didn’t notice it was from Debre Birham. Both abyssinicus and niloticus are possible there, and niloticus can also have a black stripe, but tends to be more yellowish. I think niloticus is more likely, but it’s difficult to say without exact measurements.

  • 17 February 2021
    Charles Foley

    If you saw them at 2700m my money would be on A. abyssinicus, as A. niloticus is a generally found at lower elevations.

  • 17 February 2021
    Vladimir Dinets

    A. abyssinicus only occurs above 3200 m according to recent molecular data (see Bryja et al., 2019, Annotated checklist, taxonomy and distribution of rodents in Ethiopia – I have PDF if needed). A. niloticus is apparently a species complex with both low- and high-elevation taxa.

  • 18 February 2021
    Michael Widmer

    Hi all. Thank you for all the essential and detailed comments on my question and for referring to the paper by Bryja et al. 2019. I found a free download:
    https://bioone.org/journals/folia-zoologica/volume-68/issue-3/fozo.030.2019/Annotated-checklist-taxonomy-and-distribution-of-rodents-in-Ethiopia/10.25225/fozo.030.2019.full
    Kindly regards Michael

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